Dear Friend:
Nice to greet you.

Befor I base the answer to your inquiry, I just feel to express my utter annoyance against them who market this worthy organic input, such as this Worm Casting, with arguments which don't have any base neither in a biological point of view, nor with simply logic. What they sell, is not Worm Casting any more, but a fine organic matter, which will improve the soil texture in certain grade (not in the same grade a good Worm Casting does), but in any case it will be an input which allows recover the soil fertility. No doubt that the market decision for this salers, will just improve their own incomes (and I don't think for a long time), realizing that this dehydrated sales way helps them to greatly facilitate the crop process, percolated or screened and product packed, and its distribution, due to its less price in freight, which leads to a bitchy and abusive cost reduction.
The worst part, I think, doesn't reside in the publicity deceit to accomplish their sales, furthermore in the discredit of the kindness and properties a good Worm Casting offers, since I am sure that the dehydrated product, will not lead to a real increase in any crop production. I think, this way to sale, is a real attack against the earthworm-agriculture and its workers who in a honest and technician way, develop the activity and do great efforts to share its kindness and encourage its labor in a massive way.

BASE OF THE ANSWER:

ABOUT THE ORGANIC MATTER AND THE WORM CASTING SPECIFICLY:

In the intention of not giving an answer "simplistic" and less a "boring speech", I will contribute the following basic principles on the matter that are foundation in general agronomy and very especially concerning organic agriculture.

* The synthesis and mineralization of the soil organic matter are processes governed by the "biological activities" of the soil, those that include groups of diverse microorganisms and their associate enzymes

* Since the organic matter is a source of assimilable carbon, is an ecological niche that allows the life and nutrition for a varied population of microorganisms, the one which, in definitive, is the one that regulates the contribution of nutritious to the plants and improve the physical conditions of soil.

* Additionally, the organic matter form cementing compounds of particles, such as polysaccharides and glomalines , what grants a bigger stability to the soils for the formation of stable attachés to the water.

* An Worm casting, is an excellent organic matter that possesses a high capacity of intercambio catiónico, superior to the clays, and a high de-toxic capacity of heavy metals in general.

* The present biomass in the quality worm casting is the true motor that allows working of most of the terrestrial ecosystems, allowing the development of a series of activities that are fundamental, such as:

- Control the flow of nutritious to all kind of plants.
- Control the cycle of nutritious, allowing their liberation, among them the Phosphorus that possesses a high fixation
- Contribute to the aggregation of soil particles, particularly the mushrooms, those that through their - Control the flow of nutritious to all kind of plants.
- Control the cycle of nutritious, allowing their liberation, among them the Phosphorus that possesses a high fixation
- Contribute to the aggregation of soil particles, particularly the mushrooms, those that through their micelios and glomalines liberation (cementing substances) form macros and micro - attaché to the soil.
- Contribute to the "metabolism" of other soil microorganisms, in the roll of energy source of easy degradation, realizing that for their composition, they are mainly proteid substances.

* It is a proven fact that the number of microorganisms of the soils is very superior, in natural form, in the near area of the roots or " rootsphere", that in a soil without plants, due to the continuous source of "easily assimilable carbon" that gives them the radical system through their "perspired". It is necessary to highlight that inside these "micro broad beans", the number of microorganisms and its activities are affected by such factors as "oxygen deficit, distant pH to the neutrality, deficit of nutritious, lack of light and extreme temperatures, and so forth.

* It's considered that 10% of the population of microorganisms of a soil is only active before negative factors, 90% are in " sleepy stage" and they are only activated when find a source of carbon able to metabolize.

* The heap of beneficent activities that can develop the microorganisms of the soil is mainly due to to its great"biodiversity".

* Summarizing, the contribution of organic matter to a soil, and fundamentally if it is "worm casting qualified", allows not only to improve the texture of a soil, also the rizobies presence, induces high levels of biological activity, that in turn facilitates the capture of the nitrogen of the air, the micorrizes presence, the increase of the organic acids in the soil, the solubility of the Phosphorus that possesses a high fixation grade, the regulation of the pH, among other kindness.

ABOUT SOIL FERTILITY:

* Fertility is the capacity to give life. When we speak of soil fertility, we refer to their capacity to allow and to sustain vegetable and animal life. This not only depends on the presence of nutritious in the floor, but also of its "readiness" for the plants, of the capacity to store and to give water, among other factors.

* A first measure of optimization of the biological fixation of the nitrogen, consists on not forgetting that the agents fixers are alive beings. This fixation associates to high breathing rates in the soil, what happens in presence of high biological activity for microorganisms.

* It is an utter demonstrated fact that the microorganisms of the soil are fundamental to assure a better and bigger use of the phosphorus of the soil.

FINAL COMMENT:
Based on what I've said previously, we can conclude that the microorganisms in the worm casting, which is their fundamental characteristic, really allow recovering the fertility of a degraded soil or in degradation phase. All alive being, without exclusion, requires of water, oxygen among other factors for his survival. For lack of these, simply happens the death. It doesn't exist the chance "to revive" later on with contribution of water and oxygen. Therefore, marketing a product which lacks of these vital elements, is selling an inert product, without life, and thus lacking of all effectiveness in contributing to the fertility of a soil .

I hope to have contributed to your inquiring, sincerely yours.